1. Field of the Invention
This invention relates to improving vision in a macula diseased eye and in particular to surgically inducing a prism or causing a prismatic affect in the cornea in order to displace light from the diseased macula area of the retina to an undiseased area of the retina, thereby improving eyesight.
2. Description of Related Art
Macula disease and, in particular, macula degeneration is a leading cause of blindness in adults. Macula disease involves the central area of the retina, and it is this area that is responsible for acute vision and receives most of the light focused by the cornea and lens of the eye. Macula disease very often leads to a loss of vision to a level of 20/200 or less. Since macula disease only involves the central area of the retina consisting of a few square millimeters in area, the peripheral vision is spared in the vast majority of patients. Over 95% of the retina is usually spared from macula degeneration. Since the macula is most important for acute vision such as driving, reading, etc., these patients are severely disabled despite the fact that they still maintain peripheral vision. Intraocular lenses which are implanted inside the eye in place of a surgically removed lens (usually during cataract surgery) have been designed with prisms incorporated in them in order to displace the focused light from the center of the diseased retina, i.e., the area of macula degeneration to a more healthy peripheral area of the macula. However, these lenses require opening the eye and removing the patient's own lens in order to achieve this result. Prisms can be placed in eyeglasses, but because the eye moves and the eyeglasses remain in a stationary position, this induces too much distortion and astigmatism and is not tolerated by patients.
U.S. Pat. No. 4,581,031, issued to Jeffrey E. Koziol et al., on Apr. 8, 1986, discloses an intraocular lens including a convex portion and a prismatic portion for use with patients having macula degeneration of the retina. In another U.S. Pat. No. 4,666,446, issued to Jeffrey E. Koziol et al., on May 19, 1987, an intraocular lens comprising converging and diverging optical portions are disclosed for patients having macula degeneration. The converging lens provides the patient with substantially the same vision experienced prior to implantation of the intraocular lens. The diverging lens when combined with converging lens located outside the eye provides a magnified retinal image of a given object with increased visual acuity but a restricted visual field. Thus, a patient is provided with the choice of unmagnified but peripherally unrestricted vision or magnified but peripherally restricted vision.
U.S. Pat. No. 4,759,761, issued to Vladimir Portnoy, on Jul. 26, 1988, discloses an intraocular lens with built-in mirrored surfaces which produce the effect of a folded telescope with a long focal distance. By greatly magnifying an object, a certain amount of useful vision is restored to a patient with macula degeneration.
U.S. Pat. No. 5,123,921, issued to Theodore P. Wenblin, on Jun. 23, 1992, discloses a lens for implantation into the cornea of the eye for providing correction for myopia and myopia with accompanying astigmatism wherein a corneal cap section is removed and an implant bed is created to receive the intracorneal lens.
U.S. Pat. No. 5,364,388, issued to Jeffrey E. Koziol on Nov. 15, 1994 discloses a radiant energy beam delivery system for corneal surgery wherein radiant energy beams may be focused in a linear configuration onto the external surface of the cornea or onto intrastromal areas of the cornea of an eye to ablate the cornea in a radial slot, circumferential curved slot, or lenticular pattern and thereby modify its curvature and refractive power. However, this patent relates to correcting nearsightedness and does not disclose inducing a prism into the cornea for overcoming macula degeneration by displacement of light waves away from a diseased macula area.